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and made a part of them. However, the roots of 

 some plants, under rare conditions, seem able to 

 appropriate directly the nitrogen brought to them 

 in the air which has been absorbed by rain-water. 

 Legumenous plants are fortunate in this respect; 

 an example will be given later. 



Concerning the manner in which the electric 

 light helps plants to grow, experimenters have 

 given us some valuable information; but in rela- 

 tion to the action of the current itself upon vegeta- 

 tion much needs to be learned and here is an 

 inviting field for the microscopist as well as for 

 the chemist. 



The light furnished by electricity acts upon 

 plants in a manner very similar to sunlight. It 

 stimulates the formation of chlorophyll and assists 

 in the decomposition of carbon dioxid, upon which 

 plants feed so largely. That it helps in the forma- 

 tion of starch in the leaves can be proved in a very 

 interesting manner. Keep a plant in darkness for 

 several days so that the starch may disappear from 

 its leaves. Then cover one of its leaves with a 

 piece of tinfoil, and cut a letter or figure through 

 the foil without injuring the leaf. Expose the leaf 

 to the electric light, which will stimulate the pro- 

 duction of starch in the part of the leaf which it 

 reaches through the perforations in the tinfoil. 

 After a couple of days pluck the leaf and at once 

 put it into boiling water (to render the starch solu- 

 ble), and then into alcohol (to dissolve out the 

 chlorophyll). The leaf will now be colorless, but 

 will contain dissolved starch in the parts which 



